Device-Related Thrombus After Watchman Implant

Study Questions:

What is the clinical impact of device-related thrombi after implantation of a Watchman device in patients with atrial fibrillation (AF)?


The Watchman device was implanted in 119 patients with AF who then underwent a transesophageal echocardiogram at 45 days and at 6 and 12 months post-implantation. The patients with and without a device-related thrombus were compared.


A thrombus was detected on the Watchman device in four patients (3.4%). The thrombus was identified at 45 days in two patients, at 6 months in one patient, and at 12 months in the remaining patient. Compared to the patients without a thrombus, the patients who developed a thrombus: 1) more often had persistent AF (100% vs. 40%); 2) had a larger mean device size (29.3 mm vs. 25.7 mm); and 3) more often had deviated from the protocol-mandated anticoagulant and/or antiplatelet therapy. The thrombus resolved in all patients after treatment with warfarin and aspirin for 6 months, with no recurrences after warfarin was discontinued. There were no deaths, strokes, or embolic events during approximately 4 years of follow-up.


The factors that predispose to thrombus formation on a Watchman device are persistent AF, a large device size, and deviation from protocol-mandated anticoagulant/antiplatelet therapy. The clinical outcome is favorable after short-term therapy with warfarin.


The results of this study emphasize the importance of maintaining therapy with warfarin and aspirin for 45 days then aspirin therapy indefinitely when there is complete closure of the left atrial appendage as assessed by transesophageal echocardiography at 45 days.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Noninvasive Imaging, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound

Keywords: Anticoagulants, Arrhythmias, Cardiac, Aspirin, Atrial Appendage, Atrial Fibrillation, Echocardiography, Transesophageal, Embolism, Platelet Aggregation Inhibitors, Recurrence, Stroke, Thrombosis, Warfarin

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